The present invention relates to a process for improving or enhancing the breaking strength and/or tear strength of a warp-knitted fabric as may be used in particular in adsorptive filtering materials having a protective function against chemical poisonous and/or warfare agent materials. The present invention further relates to the use of floats for improving or enhancing the breaking strength and/or tear strength of such a warp-knitted fabric. The present invention finally relates to an adsorptive filtering material having a protective function against chemical poisonous and/or warfare agent materials which is configured on the basis of a warp-knitted fabric having improved breaking strength and/or tear strength as a backing material.
There are a whole series of materials that are absorbed by the skin and lead to serious physical noxae (harm). Examples include chemical warfare agents, such as the versicatory mustard gas Yellow Cross (Hd) and the nerve gas sarin. People likely to come into contact with such poisons must wear a suitable protective outfit and/or be protected against these poisons by suitable protective materials.
Appropriate protective suits are available to protect the body, especially the extremities and the trunk. Protective suits against chemical poisons that are intended for prolonged deployment under a wide variety of conditions must not lead to heat build-up for the wearer. Air-pervious materials are therefore used in the main. Air-pervious, permeable protective suits generally possess an adsorptive layer comprising activated carbon to bind chemical poisons very durably, so that there is no danger for the wearer emanating even from badly contaminated suits.
Such protective suits shall not impair the user's freedom of movement and protect the wearer securely against any chemical exposure for a defined period. The adsorption-capable material in such protective suits is frequently a spherical adsorbent, such as activated carbon, the spherical adsorbent being bonded in sheetlike form, for example by means of an adhesive, to a textile sheetlike material serving as a backing material. Textile fabrics are often used as textile backings in prior art protective suit manufacture.
A further important requirement of such protective suits is strength on the part of the protective suit or part of the textile fabric used as a backing material. This is because any damage to the protective suit or to the textile sheetlike material used will inevitably lead to a point of entry for chemical poisons and/or warfare agent materials, so that the protective suit itself can be deprived of its protective performance by minor damage. Therefore, the choice of textile backing material plays an important part with regard to the stability of protective suits produced therefrom. The textile backing material should possess high mechanical stability and more particularly withstand even severe mechanical loading, such as high breaking and tearing forces of the kind encountered in military deployments for example.
Prior art protective suits, which frequently comprise simple textile wovens as textile backing material for the adsorbents, are often unable to meet these high requirements with regard to mechanical stability, in particular with regard to their breaking and/or tearing behavior, so that prior art protective suits do not always ensure optimal protection against chemical poisons and/or warfare agent materials under extreme conditions in particular, for example when the soldier or wearer is in a battle scenario, since the protective suit can suffer damage under this stress in that it can tear in particular.
Similarly, the need for protective suits to meet the requirements of a long wearing period and an attendant washability immediately results in the need for textile backing materials possessing high mechanical strength.
As well as the military deploying protective suits, in particular for protection against chemical warfare agents, such as NBC warfare agents, the chemical industry also utilizes protective suits, for example to protect against toxic gases of the kind generated in numerous manufacturing operations. For this reason, the employees in question and also members of the fire service or of disaster control taskforce have to be equipped with specific protective suits to be safe during their deployment. In the event of any deployment, the protective suit is temporarily exposed to extreme physical and mechanical stresses which it must withstand without loss of its protective functions in order that the risk of contamination may be minimized.
Against this technical background, then, the present invention has for its object to provide an adsorptive filtering material having a protective function against chemical poisonous and/or warfare agent materials which is suitable for producing protective suits and at least essentially obviates or alternatively at least ameliorates the above-described disadvantages of the prior art.